Heat exchanger with wire heat conductors



Jan. 6, 1942. R. VON LINDE 2,268,680

HEAT EXCHANGER WITH WIRE HEAT CQNDUCTORS- Filed June 6, 1939 INVENTOR Eoaser v- LINDE ATTORNEYS Patented Jan. 6, 1942 v n w EXCHANGER wrrn Winn HEAT I v CONDUCTORS Robert-Von 'Linde, Obermcnzing, near Munich, 3 Germany Application June 6, 1939, Serial No. 277,664 v Y In Germany June 8, 1938 1 Claim. (Cl. 257-263) The present invention relates to heat exchangers (heating or'cooling elements) of the type wherein, in order to increase the heat exchanging surface, wire heat conductors designed as fins are arranged on the outer periphery of a tube, duct or the like which separates the media between which the heat is to be exchanged. Known heat exchangers of this type consist of spirally wound wire fins which are wound, for example, around the outer periphery of a tube, in spiral or circular formation. The production of an untwisted and noninterlaced helical wire fin of the most eiiective type, from laterally flattened and closely spaced wires is an involved process and requires complicated machinery.

The wire conducting fins are as a rule secured by means of wires which are passed through the windings of the fin and which must be inserted in the machine simultaneously with the winding of the fin. These wires press those parts of the fin which rest on the heat exchanging wall against said wall, or, if they consist of soldering material, they secure the wires to thewall when heated. This latter method which is the better of the two, demands the use of materials specially suitable for soldering. Materials which may be suitably connected to the walls only by means of hard soldering or welding, such as for example aluminium and its alloys are not suitable for the manufacture of the known heat exchangers of this type. To prevent inadmissibly high temperatures from arising in the conducting parts of the wire fins, welding electrodes must be applied to those parts of the wire which rest on the walls, but this is rendered impossible by the other parts of the wire windings.

The present invention enables the process of resistance welding or soldering to be used for the manufacture of heat exchangers of the known type and thus greatly simplifies the production of wire conducting fins and consequently of heat exchangers. This is attained according to the invention by designing the connecting yokes between the wire conducting parts of the fin by which each pair of conducting parts is secured to the wall, so as to lie in open common lanes formed by said parts on said wall so as to be easily accessible through said lanes for the application of the securing means for the fins.

These wire conducting fins may be manufactured, without interlacing, by means of simple bending or kinking tools and machines, and any wires which may be necessary for securing the connecting yoke do not interfere with the finishconnecting yokes until the wire conducting-fins are applied to the heat exchanging wall. Moreover welding electrodes may easily be inserted into the lanes formed between the conducting wires, thus enabling the connecting yokes to be welded at one point or hard-soldered to the wall without the remaining parts of the fln becoming overheated and consequently being softened.

Thus it is possible to manufacture heat exchangers of this type from aluminium, magnesium and their alloys, which metals are particularly suitable for heat exchangers on account of their small weight and their good heat conducting properties, but which formerly could not be used for this purpose, for the reasons named above.

Further advantages will be described in the following specification, in which the examples shown in the accompanying drawing are explained.

Figuresv 1 1:03 show intermediate shapes for producing wire bands in U or V form;

ing process, since they need not be applied to the v Figures 4 and 5 are fins;

Figure 6 is a cross section of a heat exchanger tube;

Figure 7 is a longitudinal shown in Fig. 6;

Figures 8 and 9 show two separate wire bands secured to a conducting wall, one within the other;

Figures 10 and 11 show a modification of the heat exchanging device shown in Figures 8 and 9.

In making a wire conducting fin, the wire is first of all bent into U-shapes as'shown in Figs. 1 and 2, or into V-shapes as in Fig. 3. Figs. 4 and 5 show, in perspective, the finished form of wire fins of the type shown in Figs. 1-3, the connecting yokes 2'of which are formed by bending back the wire conductor parts 3. This bending may be effected in known manner on a kinking machine or by means of bending rollers. The completed fins shown in Figs. 4 and 5 may obviously be manufactured in one process by means of perspective views of wire section of the tube suitable bending or kinking devices without first of all producing the intermediate shapes shown in Figs. 1-3.

Fig. 6 shows a cross section of a tube I carrying a heating or cooling agent, round which is partially applied a wire conducting fin of the type shown in Fig. 4. A binding wire 5 is tightly wound on to the connecting yokes 2 either after or simultaneously with the application of the fin, which wire presses tightly the yokes 2 to the wall of the tube I.

Fig. '1 which is a longitudinal section through the heat exchanging tube as shown in Fig. 6,

shows that the connecting yolzesmay be made more accessible for the application of a welding electrode I, if the conducting wires 3 are bent obliquely outwards from the connecting yoke 2.

After welding, the conducting wires may be bent back by means of a suitable device so that they stand at right angles to the periphery of the tube. 7

As will be seen from Figs. 8 and 9, two separate wire fins may be disposed one within the other and their-conducting parts 3, 3' may be wall. In this case the connecting yokes 2, 2' which are secured to the wall I and whichin the examples shown are of the same length, lie one behind the other in the same easily accessible lanes 4 extending in the direction of the fin,

The example shown in Figs. 10 and 11 difiers from that described above simply in that the connecting yokes 2" of one of the fins are longer bent at different angles to the heat exchanging than the yokes 2 of the other fin, and that the conducting wires 3" are parallel to the conducting wires 3. a

Having now particularly described the nature of my said invention and in what manner the same is to be performed, I declare that what I claim is: I

A continuous wire fin for a heat exchange tube arranged on said tube substantially as a helix, said helix comprising two rows of inverted U or V-shaped loops of wire, the loops of one row being staggered with relation to those of the other row and the terminal leg of each loop in each row being integrally joined to the initial leg of the next staggered loop of the other row by a section of wire substantially normal to the direction of the rows of loops, the normal sections being accessible between said rows of loops for attaching the sections to the tube; thereby supporting said helix.

' ROBERT voN LINDE. 

